DESCRIPTION: (Applicant's Abstract) The National Household Survey on Drug Abuse (NHSDA) represents a major effort to monitor drug use in the population. Results from the surveys are released annually, providing important information about the prevalence of use in the US. The data on dependence symptoms and functional impairment remain to be analyzed. This competing continuation proposal requests 4 years of support to carry out further analyses of multiple waves of the NHSDA to investigate selected issues related to substance dependence and abuse for four drug classes; marijuana, cocaine, cigarettes and alcohol. During the current two-year period of support, we developed approximations to DSM-IV definitions of substance dependence and abuse and investigated the extent of drug dependence in the population in different sex, and racial/ethnic groups, and the relationships of dependence to extent of use. In this next period, six issues will be investigated. This relationship between dependence and abuse and progression along the developmental sequence of involvement in drugs; (2) The extent of familial similarity on drug use and dependence between parents and adolescents, and siblings, (3) The relationship of user dependence and abuse with selected psychiatric symptoms among adults and behavioral and emotional problems among adolescents; (4) The relationship between dependence and abuse and participation in treatment; (5) The relationship between dependence and risk behaviors for HIV/AIDS; (6) The relationship between overall prevalence of drug use in the nation and rates of dependence and abuse. Analyses will be conducted for age, sex and ethnic specific groups, and will be based on multiple surveys from 1988-1997(N = 8,038 to 32,594). By aggregating data from 3 surveys, we expect 4,650 parent-child and 2,330 sibling pairs. The oversampling of youths and minorities in the NHSDA and the inclusion of nicotine make possible age-, gender and racial/ethnic-specific analyses and comparisons across drugs rarely feasible in any other study. The study will extend our understanding of the extent of serious drug use in the nation, the etiology of substance dependence/abuse. The extent of treatment needs, the relationship between risk behaviors for AIDS and drug dependence, and racial/ethnic differences in patterns of use, dependence/abuse, comorbidity and treatment experiences in the population. Such questions by and large have not been treated in the epidemiological literature on drug use in the general population, which has focused almost exclusively on frequency measures of drug use.